So Phil - a welded box and this unwelded segmented cylinder are both good very simple test cases for Octane.

It's really important for both of these simple cases (or at the very least the unwelded case) to work in order for CAD data to be handled well.

As best that I can tell, the problem is that the vertex normals in the OBJ file are not being used for doing the shading.

If they were, then the box would have flat looking faces instead of having improper smoothing applied there, and the cylinder would have smooth looking faces instead of having improper creasing applied in that case.

- Michael